Graphical Solution to Simultaneous Equations (SQA National 5 Maths): Revision Note

Solving simultaneous equations graphically

How do I solve linear simultaneous equations graphically?

• The solutions to simultaneous equations can be seen on a graph of the two equations

  • If the graph is not provided, plot both equations on the same set of axes

    • To do this, you can use a table of values

      • or rearrange into y = mx + c  if that helps

• Find where the lines intersect (cross over)

  • The x and y solutions to the simultaneous equations are the x and y coordinates of the point of intersection

• For example, to solve 2x - y = 3 and 3x + y = 4 simultaneously

  • First plot them both on the same axes (see graph)

  • Find the point of intersection, (2, 1)

  • The solution is x = 2 and y = 1